Sparking plug for internal-combustion engines.



R. F. HALL.

SPANNING PLUG PON INTERNAL coMBUsTloN ENGINES.

APPLICATION FILED OUT. 30, 1908.

976,797. Patented N0v.22,191o.

WITNESSES f INVENTOR loerflja/Z. Aecm/ j cleaning or other purposes and readily re-` UNITED sTArns PATENT OFFICE.

ROBERT FREDERICK HALL, 0F lllIOSILLEY,r BIRMINGHAM, ENGLAND.

.SARKING IKPLUG FOR INTERNAL-COMBUSTIUN ENGINES.

Specication of Letters Patent.v Application led October 30, 1908. Serial No. 460,320.

Patentednoviee, 1910;

I To all whom it may concern:

tion systems of' internal combustion engines,

andhas foriitstobjects to provide an improvedy construction of plug of which the parts `can be' readily taken' to pieces for placed; whichuobviates all shoulders, ledges orannular.groovesI which, in ordinary plugs, form restingplaces and receptacles for carbon deposits; which obviates the use of asbest-0s or other packing, whichk is liable to absorb oil ladened with carbon and whichv also is porous; andfwhichlobviates danger,

of fracture when tightening up the?. parte.`

Figure 1 of the accompanyingY drawings represents a section through a sparking plug constructed in accordance with this invention. Fig. Q is a transverse section on line a: Fig. 1. Fi 3 shows the component parts .of the plug isassembled from one another.

The same letters of reference indicate corresponding parts ineach of the figures of the drawi n l i p The insulgzitor body part of the -plug`,"which d surrounds the central electrode or conductor rod, and serves to insulate 'same from the metallic body or shell a, consists of along onepiece sleeve b madeA of steatite, porcelain or other suitable insulating material. n The central hole or bore b1 of this sleeve, and

through which the conductor rod passes, is,

tapered throughout its length, the wider end being situated at the inner endof the plug and extending to near the sparking points. The conductor rod itself is made 1n two parts a, d. The part c extends throu h the outer end of the sleeve b where it is a apted to be connected by the terminal nutsd, c2, with the high tension cable of the ignition system. The inner end of the said part c is formed' with an enlarged head cs whose outer sides are tapered to correspond to the internal taper of the insulator b, while also a number of annular gas-check grooves or rings c* are formed which serve to prevent the passage of gas betweenthe conductor rod points d2.

and said insulator. The said taper head cr. l

is arranged to make an interlocking and wedging connection with the taper interior of thesleeve b, and vis' retained in positionv by the 4lock nut 05 taking itsfbearing upon the end of said'sleeve b.e The tendency of the explosions inv the engine cylinder'is to tighten the joint between the conductor rod and insulator by forcingthe part e farther outward and thus the taper' head c? into closer wedging engagement .with said ,insulator.l Between the rod 'c and the` inside "taper wallsvof the insulator sleeve b an zanz nular clearance e is formed.' .Y The lower half d' of the conductor rod consists. preferably of' a4 pure nickel: lrod whose inner end d1 is 'screwed 'into thehead c3 of the part c, while the outer end is 'bifur..

cated', and' formed into the two' sparking The' outer half of the sleeve 1b is also taperedexternally, and is 'adapted'to end of` the metalbody. a. The .innerY end f? of this sleeve f is, after the-insulator b hasl In order to rendenth'e'"jointrbetween the Y y eo---v sleeve f and insulator b gas tight, a series ofgas-.check annular rooves or rings b may be provided aroun the latter.

The interior of the body a is tapered as shown, and the inner half of the insulator b is tapered correspondingly and is separated from said body by an annular space g. The said inner end of the 4insulator thus serves as a shield for assistin in preventing shortcircuiting due to carbonaceous deposits, being separated from both central and outer electrodes by annular spaces. By removing the lock nut c5- the central electrode may be taken out of the insulator and cleaned and replaced. The long taper hole of said insulator admits of being readily cleaned when required. As can beseen, the taper part on the central rod comes directly .in line with that part of the external portion of the insulator which is en aged and gripped b the sleeve f, so that t ere is no danger o said insulator bursting or fracturing when the electrode is tightened up.

eol

-make a locking .wedge connectionI with a. 4metallic: sleeve, f having-a correspondingly -tapered interior, and screwedinto thefouter Having fully described my invention, what l desire to claim and secure by Letters Patent is l. A spark plug for ex losive engines comprising an insulator body tapered externally so as to diminish in diameter toward the outer end of the plug and also having a tapered bore which diminishes in diameter toward the outer end of the, plug, a metal attaching shell adapted to serve as one of the electrodes of the plug, a metallic sleeve having an internal taper corresponding to and cooperative with the external taper upon the insulator body, said sleeve havin a rigid gas-tight connection with said shel ,and a 'conductor'extendirg throughfthe bore of the insulator body and having a tapered part which corresponds to and coperates with the wall of the tapered bore of the insulator body, the tapers upon the exterior of the,

insulator body and the cooperating-sleeve, and also the taper of the bore of such insulator body and tapered portion of the conductor being such that the pressure of the gas acting upon the inner end of the plug will tend to tighten such parts.

2. A sparking plug for internal combustion engines, having an insulator bod part plrovided with a hole which tapers uniformly om end vto end of the insulator body part,

and a central conductor rod provided with an enlarged taper-sided collar ada ted to make a locking wedge connection irectly with the Wall of the internal hole in the body, said taper-sided part of the rod being provided with annular gas-check rings or grooves. Y

3. A spark plug for explosive engines comprising a metal attaching shell capable of serving as an electrode, an insulator body 40 fitted therein and provided with a bore which tapers from end to end thereof, the

wider portion of the bore beingarran ed at the inner end of the plug, and a con uctor rod having a short tapered collar directly engaging and forming a gas-tight joint within said tapered bore, and an electrode extending inwardly from said collar, the inner end oi'rtheinsulator-bodybein'garranged .between the metallic'shell and the inclosed 50 portion of the electrode and being separated from said shell and electrode by annular spaces.

In testimony whereof I have hereunto set my hand in presenceof two subscribing wit- 

